Linear Motor System

ABSTRACT

A linear motor system includes a coil assembly and a magnet assembly disposed adjacent to the coil assembly. The coil assembly includes a plurality of coil windings and a sealing material to seal and to prevent moisture and/or chemical ingress into the coil windings. The magnet assembly includes a plurality of magnets, a magnet housing disposed to house, cover and seal the plurality of magnets within the magnet housing, a plate to cover the plurality of magnets, a sealing element disposed between the plate and the magnet housing to seal the magnet assembly, and a groove formed to receive the sealing element between the plate and the magnet housing.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/789,320, entitled “Sealed Linear Motor System”, filed May 27, 2010,which is herein incorporated by reference.

BACKGROUND

The invention relates generally to linear motors, and particularly to alinear motor system with a single bearing rail for ease of assembly andimproved performance.

Linear motors are known in the art and are used in a variety ofapplications such as machining, robotic positioning and food processingand packaging applications. One type of a linear motor system includesstationary armatures having coils and movable stages containing magnets.Typically, the armature windings may be mounted to a base plate and astage with a series of magnets is free to move on the base plate. Thestage is guided in a desired direction by applying AC or DC excitationto the coils. Another type of linear motor system includes stationarymagnets and moving coils.

In certain applications, the linear motor systems may be subjected toloads that may cause stresses on alignment structures of the motorsystems. For example, side loading may occur that can cause bearings toexert forces on guide rails and other structures in ways that may leadto early wear and limit the life of the motors. Moreover, many linearmotor systems comprise a pair of rails or guides that bear such sideloading. These must generally be aligned with one another to avoidunwanted excessive side loading that can similarly lead to acceleratedwear and limit life. Careful alignment of parallel rails of this typecan be demanding during manufacturing and assembly.

Accordingly, it would be desirable to develop a linear motor system thatcan be employed in applications where side and other loading isanticipated.

BRIEF DESCRIPTION

Briefly, according to one embodiment of the present invention, a sealedlinear motor system is provided. The sealed linear motor system includesa sealed coil assembly having a plurality of coil windings within a baseplate and comprising covers disposed about the base plate and coilwindings to prevent moisture and/or chemical ingress into the base plateand the coil windings. The sealed linear motor system also includes asealed magnet assembly disposed adjacent to the coil assembly andcomprising a plurality of magnets mounted on a magnet mounting plate anda magnet housing disposed on a surface of the magnet mounting plate tocover and seal the plurality of magnets within the housing.

In accordance with another aspect, a sealed linear motor system isprovided. The sealed linear motor system includes a sealed coil assemblyhaving a plurality of coil windings within a base plate and comprisingcovers disposed about the base plate and coil windings to preventmoisture and/or chemical ingress into the base plate and the coilwindings. The sealed linear motor system also includes a sealed magnetassembly disposed adjacent to the coil assembly and comprising aplurality of magnets mounted on a magnet mounting plate and a magnethousing disposed on a surface of the magnet mounting plate to cover andseal the plurality of magnets within the housing. The sealed linearmotor system further includes a motor stage structure secured to thecoil assembly or to the magnet assembly and configured to receive amovable machine component and a bearing assembly coupled between thecoil assembly or the magnet assembly and the motor stage structure andconfigured to facilitate linear motion of the magnet assembly relativeto the coil assembly.

In accordance with another aspect, a sealed linear motor system isprovided. The sealed linear motor system includes a sealed coil assemblyhaving a plurality of coil windings within a base plate and comprisingcovers disposed about the base plate and coil windings to preventmoisture and/or chemical ingress into the base plate and the coilwindings. The sealed linear motor system also includes a sealed magnetassembly disposed adjacent to the coil assembly and comprising aplurality of magnets mounted on a magnet mounting plate and a magnethousing disposed on a top surface of the magnet mounting plate to coverand seal the plurality of magnets within the housing. Further, thesealed linear motor system includes at least one encoder sensor sealedwithin the coil assembly and configured to sense position and/or motioninformation of the magnet assembly.

In accordance with another aspect, a sealed linear motor system isprovided. The sealed linear motor system includes a sealed coil assemblyhaving a plurality of coil windings within a base plate and includingcovers disposed about the base plate and coil windings to preventmoisture and/or chemical ingress into the base plate and the coilwindings. The sealed linear motor system includes a sealed magnetassembly disposed adjacent to the coil assembly and comprising aplurality of magnets mounted on a magnet mounting plate and a magnethousing disposed on a top surface of the magnet mounting plate to coverand seal the plurality of magnets within the housing. The sealed linearmotor system also includes a sealed sensor assembly disposed adjacent tothe magnet assembly and having at least one encoder sensor configured tosense position and/or motion information of the magnet assembly.

DRAWINGS

These and other features, aspects, and advantages of the presentinvention will become better understood when the following detaileddescription is read with reference to the accompanying drawings in whichlike characters represent like parts throughout the drawings, wherein:

FIG. 1 illustrates a sealed linear motor system in accordance withaspects of the present technique.

FIG. 2 is an exploded view of the stator assembly of FIG. 1 inaccordance with aspects of the present technique.

FIG. 3 is an exploded view of the magnet assembly of FIG. 1 inaccordance with aspects of the present technique.

FIG. 4 is a perspective view of the sealed linear motor system of FIG. 1in accordance with aspects of the present technique.

FIG. 5 illustrates an exemplary configuration of an encapsulated sensorassembly employed in the sealed linear motor system of FIG. 4.

DETAILED DESCRIPTION

As discussed in detail below, embodiments of the present techniquefunction provide a sealed linear motor system for use in applicationssuch as food processing applications, wet installations and chemicalladen environments. In particular, the sealed linear motor systemincludes individually sealed coil and magnet assemblies to preventmoisture and/or chemical ingress within the system.

References in the specification to “one embodiment”, “an embodiment”,“an exemplary embodiment”, indicate that the embodiment described mayinclude a particular feature, structure, or characteristic, but everyembodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed.

Turning now to drawings and referring first to FIG. 1, a sealed linearmotor system 10 is illustrated. The system 10 includes a coil assembly12 and a magnet assembly 14 disposed adjacent to the coil assembly 12.The system 10 further includes a bearing assembly 16 coupled to themagnet assembly 14 and configured to facilitate linear motion of themagnet assembly 14 relative to the coil assembly 12. The coil assembly12 includes a plurality of sealed coil windings laminated on an ironcore. Further, the magnet assembly 14 includes a plurality of magnetscovered by shrouds.

In operation, the coil assembly 12 is configured to receive power from apower source (not shown in FIG. 1) such as a three-phase power supply.The bearing assembly 16 includes a rail 18 that facilitates movement ofthe magnet assembly 14 along the coil assembly 12. This bearing assembly16 may include two or more bearing elements (not shown) that engageelongated recesses in the rail 18 to hold the magnet assembly 14 on thecoil assembly 12, while allowing it to move along the coil assembly 12.A controlled magnetic field produced by the coil assembly 12 acts on themagnet assembly 14 to produce a linear force for driving the magnetassembly 14 and any external load secured to it.

In the illustrated embodiment, the system 10 includes a top plate 20 tosecured to the magnet assembly 14. Further, the system 10 also includesside supports such as represented by reference numerals 22 and 24 tolink the top plate 20 to any other support structures, such as a lowersupport plate.

In the illustrated embodiment, each of the coil assembly 12, the magnetassembly 14 and the bearing assembly 16 have an environmentallyprotected design as will be described in detail below. Moreover, thematerials for each of these components are selected for use inenvironments such as wet installations, chemical laden environments,among others. In a presently contemplated embodiment, the externalshells of the assemblies are made of stainless steel.

It should also be noted that the arrangement shown in FIG. 1 may bereferred to as a motor stage. The plates and supports associated withthe linear motor may take various forms in such a motor stage, but aretypically designed to support a moving component. That is, in anembodiment in which the coil assembly 12 is stationary, it will besecured to a machine and powered by an external power source (such asthree-phase power supplied via any desired switchgear, circuit breakers,and so forth. The power may be controlled to regulate movement of themagnet assembly 14 along the coil assembly 12 via the bearing rail. Themoving machine component, secured to the stage, such as via fastenersinterfacing with the supports around the magnet assembly may thus bemade to move to desired locations. The stage may be used for a widevariety of operations, such as pick-and-placement, material handling,containing forming, just to mention a few.

Furthermore, it should be noted that in the illustrated embodiment, thecoil assembly 12 is designed to be stationary, while the magnet assembly14 moves along it. The arrangement may be reversed, such that a sealedcoil assembly 12 moves along a sealed magnet assembly 14. In such cases,the two assemblies 12 and 14 may be sealed with techniques such as thosedescribed below.

Still further, the particular stage arrangement may employ variousbearing configurations. In the illustrated embodiment, a single bearingrail is provided on the upper side of the coil assembly 12. In otherembodiments, the bearing assembly 16 may be provided on the lower side,and other bearing techniques may be used. Similarly, the entirearrangement may be inverted or otherwise positioned, such that eitherthe coil assembly 12 or the magnet assembly 14 may be located on top ofthe combined structure, or the structure may be positioned at variousangles other than horizontal.

In certain exemplary embodiments, the system 10 may include positionsensors, such as Hall-effect sensors coupled to the coil assembly 12 forsensing position information of the magnets of the magnet assembly 14.In certain other embodiments, the system 10 may include such sensors inan encapsulated assembly external to the coil assembly 12. Theencapsulation of the sensors prevents any moisture ingress into thesensors.

FIG. 2 is an exploded view 30 of the coil assembly 12 of FIG. 1 inaccordance with aspects of the present technique. As illustrated, thecoil assembly 30 includes a plurality of coil windings 32 with an ironcore laminated over a base plate 34. In this exemplary embodiment, thebase plate 34 is made of stainless steel. In the illustrated embodiment,the coil windings 32 are disposed in coil retainers such as representedby reference numeral 36.

The coil assembly 30 further includes a top cover 38 and side coversrepresented by reference numerals 40 and 42 disposed about the coilwindings 32 and the base plate 34. In the illustrated embodiment, thetop cover 38 and the side covers 40 and 42 may be bolted to thelamination stack. The top cover 38 and the side covers 40 and 42 areconfigured to prevent moisture and/or chemical ingress into the baseplate 34 and the coil windings 32. In one exemplary embodiment, the topcover 38 and the side covers 40 and 42 are made of stainless steel.However other suitable materials may be employed for the top cover 38and the side covers 40 and 42.

In this exemplary embodiment, a sealing material is employed to bond andseal the plurality of coil windings 32 to the base plate 34. In oneexemplary embodiment, the sealing material includes a resin. In thisexemplary embodiment, the sealing material includes thermal conductingepoxy such as manufactured and marketed by Emerson & Cummings Stycastthat is commercially available in the market. The base plate 34 includesa plurality of grooves and encapsulation plugs such as represented byreference numeral 44 for sealing the coil windings 32 with the sealingmaterial. Furthermore, sealing washers 46 are disposed on the base plateto prevent leakage of moisture and/or chemicals into the coil windings32 and the base plate 34. In this exemplary embodiment, the sealingwashers 46 include nylon.

The coil assembly 34 further includes end caps 48 and 50 disposed onboth ends of the coil windings 32. In this exemplary embodiment, the endcap 48 includes components for facilitating electrical connections ofthe coil assembly 30 with a power supply and/or a controller. Where aninternal encoder sensor is provided, as in the illustrated embodiment,two such electrical connections may be provided, one dedicated tosupplying power, and the other for conducting sensed position signals.Both connections are sealed.

The coil assembly 34 further includes a printed circuit board 52 havingat least one encoder sensor for sensing position and/or motioninformation of the magnet assembly 14 (see FIG. 1). As will beappreciated by those skilled in the art, the sensed signals may beprocessed (at least partially) within the coil assembly 12, or fully byexternal circuitry. In either case, position signals may be used toderive velocity signals and acceleration signals, where desired, and anysuch signals may be used as feedback to accurately position and move thestage as needed in the particular application.

The printed circuit board 52 may be coupled to the base plate 34 usingany suitable connecting arrangement. In this exemplary embodiment, abracket 54 is employed to connect the printed circuit board 52 to thebase plate 34. In this example embodiment, the at least one encodersensor includes an analog Hall-effect sensor mounted on the surfacemounted printed circuit board 52.

As will be appreciated by those skilled in the art, the coil assembly 34may include other suitable components such as sealed cable connectors 56and 58 for facilitating connection with a power supply and a controllerrespectively.

As can be seen, the components of the coil assembly 32, such as thecoils 32, the base plate 34 and the printed circuit board 52 with theencoder sensors are sealed using corrosion resistant materials in astainless steel housing. Further, the coil assembly 32 is fullyencapsulated and sealed with epoxy matrix to prevent ingress of moistureand/or chemicals into the coil assembly 32.

FIG. 3 is an exploded view 70 of the magnet assembly 14 of FIG. 1 inaccordance with aspects of the present technique. As illustrated, themagnet assembly 70 includes a plurality of magnets such as representedgenerally by reference numeral 72, mounted on a magnet mounting plate74. The magnets 72 may be mounted on the magnet mounting plate 74 usinga suitable adhesive. A magnet housing 76 is disposed on a top surface 78of the magnet mounting plate 74 to cover the plurality of magnets 72. Inthis exemplary embodiment, each of the magnet mounting plate 74 and themagnet housing 76 is made of stainless steel.

The magnet assembly 70 further includes a sealing material configured toplace and seal the magnet mounting plate 74 and the magnet housing 76.In one exemplary embodiment, the sealing material is an elastomer. Inthe illustrated embodiment, O-ring seal is disposed between the magnetmounting plate 74 and the magnet housing 76.

The magnet mounting plate 74 may include grooves for laying a O-ringseal 80 between the magnet mounting plate 74 and the magnet housing 76.In certain embodiments, the O-ring seal comprises elastomers such asethylene propylene, fluorocarbon, neoprene, nitrile and silicone.

In certain embodiments, the sealed magnet assembly 70 may be mounted toan external mounting plate 82 via fasteners such as represented byreference numeral 84. In the illustrated embodiment, the magnet assembly70 also includes a linear guide 86, corresponding to rail 18 shown inFIG. 1, configured to facilitate the movement of the magnet assembly 70.

In this exemplary embodiment, the magnet assembly 70 further includes amagnetic encoder scale (not shown) mounted to the magnet assembly 70.The magnetic encoder scale is configured to produce an outputcorresponding to the position and/or motion information of the magnetassembly 70. In the illustrated embodiment, the magnet assembly 70includes other suitable components such as block stops 88 and 90 forcontrolling the movement of the magnet assembly 70. As can be seen, themagnet assembly 70 with the plurality of magnets 72 and the magneticencoder scale are sealed in stainless steel housing, thereby protectingthe magnets 72 from moisture and/or chemicals during wash downoperations such as required in food processing and other applications.

FIG. 4 is a perspective view 100 of the sealed linear motor system 10 ofFIG. 1. As illustrated, the system 100 includes the coil assembly 12,the magnet assembly 14 and the bearing assembly 16 disposed within astage support steel housing 102. As described before, each of thesecomponents employ corrosion proof materials such as stainless steel.

In the illustrated embodiment, the stage support housing 102 includes amotor stage structure configured to receive a movable machine component.The motor stage structure includes the top plate 20 and the sidesupports 22 and 24 configured to support the top plate 20. The top plate20 is coupled to the bearing assembly 16 and the side supports 22 and 24through fasteners 104 such as through a screw and washer arrangement. Asillustrated, the top plate 20 and the side supports 22 and 24 providestructural integrity of the system 100 while providing supports for thecoils 32 (in the coil assembly 12) and magnets 72 in the magnet assembly14. The top plate 20 further includes encapsulation plugs such asrepresented by reference numeral 106 for sealing the system 100 using asealing material.

In the illustrated embodiment, the bearing assembly 16 includes thelinear guide 86 and other components such as bearings to guide themovement of the magnet assembly 14. Further, the bearing assembly 16also includes the block stop such as represented by reference numeral 88for controlling the movement of the magnet assembly 14. The system 100also includes other suitable components like the cable connectors 56 and58 for connection of electrical cables while providing strain relief atthe connection points.

In certain embodiments, the components of the coil assembly 12, themagnet assembly 14 and the bearing assembly 16 are passivated andelectropolished thereby resulting in a smooth surface to facilitate washdown of the components. In the illustrated embodiment, the components ofthe system 100 are assembled with suitable clearances and air gapsbetween the parts to facilitate minimum build-up of material in thesystem 100 for easy wash down of such components.

Furthermore, compliant sealing materials such as elastomers are utilizedto seal such components. The bearing assembly 16 may include stainlesssteel bearings and food grade grease. Moreover, the components areassembled to avoid any possible water traps in the assembly of thesealed linear motor system 100. In the illustrated embodiment, theinterior spaces of the coil assembly 12 and the magnet assembly 14 arefilled with a potting material after the components are assembled. Inthis exemplary embodiment, the assembly is sealed using thermalconducting epoxy.

As can be seen, the individually sealed components such as the coilassembly 12 and the magnet assembly 14 along with other components ofthe sealed linear motor system 100 are protected from moisture and/orchemical ingress within the housing 102 with the top plate 20, sidesupports 22 and 24 and the sealing material.

In certain embodiments, the sealed linear motor system 100 may includeencoder sensors in an encapsulated assembly external to the coilassembly 12. The encapsulation of the sensors prevents any moistureingress into the sensors. FIG. 5 illustrates an exemplary configuration120 of an encapsulated sensor assembly. The sensor assembly 120 includesa stationary enclosure 122. Further, the sensor assembly 120 includes amovable enclosure 124 disposed about the stationary enclosure 122 withthe magnet assembly.

In the illustrated embodiment, each of the stationary and movableenclosures 122 and 124 is made of stainless steel. The stationaryenclosure 122 includes a printed circuit board 126 having encoder sensorarrays such as represented by reference numerals 128 for sensingposition and/or motion information. In addition, the printed circuitboard 126 includes Hall effect magnetic commutators represented byreference numeral 130.

The sensor assembly 120 further includes encoder magnets 132 andcommutation magnets 134. In addition, the sensor assembly 120 includes amagnet mounting bar 136 that moves along with the movable enclosure 124.The sensor assembly 120 further includes other suitable components suchas a linear guide bushing 138, an end cap 140 and a linear seal 142 forsealing the end of the assembly 120. It should be noted that thecomponents described above may be made of suitable corrosion resistantmaterials.

As will be appreciated by those skilled in the art, the sensed signalsfrom the sensor assembly 120 may be processed (at least partially) via aprocessing circuitry within the assembly 120, or fully by externalcircuitry. The sensor assembly 120 may be coupled to the linear motorsystem 100 using any suitable coupling mechanism. In one exemplaryembodiment, the sensor assembly 120 is bolted to the linear motor system100. In certain embodiments, the sensor assembly 120 includes integralwipers and self aligning guide bearings. In the illustrated embodiment,interior spaces of the sensor assembly 120 are filled with a pottingmaterial.

The various aspects of the structures described hereinabove may be usedfor sealing linear motor systems for use in high pressure wash down orin wet environments. As described above, the technique utilizes sealingfeatures and materials for preventing moisture ingress from highpressure wash down thereby allowing use of such systems in wetapplications and in applications with hostile environments such asexplosive environments. As will be appreciated by those skilled in theart, the use of such sealing mechanisms substantially enhances thesurvivability and reliability of such linear motor systems in wetinstallations, chemical laden environments and explosive environments.

While only certain features of the invention have been illustrated anddescribed herein, many modifications and changes will occur to thoseskilled in the art. It is, therefore, to be understood that the appendedclaims are intended to cover all such modifications and changes as fallwithin the true spirit of the invention.

1. A sealed linear motor system, comprising: a sealed coil assemblyhaving a plurality of coil windings and a sealing material to seal andto prevent moisture and/or chemical ingress into the coil windings; anda sealed magnet assembly disposed adjacent to the coil assembly andcomprising a plurality of magnets, a magnet housing disposed to house,cover and seal the plurality of magnets within the magnet housing, aplate to cover the plurality of magnets, a sealing element disposedbetween the plate and the magnet housing to seal the magnet assembly,and a groove formed to receive the sealing element between the plate andthe magnet housing.
 2. The sealed linear motor system of claim 1, wherethe groove is formed in the magnet housing.
 3. The sealed linear motorsystem of claim 1, wherein the sealing material is configured to sealthe coil windings to a base plate.
 4. The sealed linear motor system ofclaim 3, wherein the sealing material comprises thermal conductingepoxy.
 5. The sealed linear motor system of claim 3, further comprisingsealing washers disposed on the base plate and configured to preventleakage of moisture and/or chemicals into the coil windings and the baseplate.
 6. The sealed linear motor system of claim 5, wherein the sealingwashers comprise nylon.
 7. The sealed linear motor system of claim 1,wherein each of the plate and the magnet housing comprises stainlesssteel.
 8. The sealed linear motor system of claim 1, wherein the sealingelement comprises an elastomeric seal disposed between the plate and themagnet housing.
 9. A sealed linear motor system, comprising: a sealedcoil assembly having a plurality of coil windings and a sealing materialto seal and to prevent moisture and/or chemical ingress into the coilwindings; a sealed magnet assembly disposed adjacent to the coilassembly and comprising a plurality of magnets, a magnet housingdisposed to house, cover and seal the plurality of magnets within themagnet housing, a plate to cover the plurality of magnets, a sealingelement disposed between the plate and the magnet housing to seal themagnet assembly, and a groove formed to receive the sealing elementbetween the plate and the magnet housing; a motor stage structuresecured to the coil assembly or to the magnet assembly and configured toreceive a movable machine component; and a bearing assembly coupledbetween the coil assembly or the magnet assembly and the motor stagestructure and configured to facilitate linear motion of the magnetassembly relative to the coil assembly.
 10. The sealed linear motorsystem of claim 9, wherein the motor stage structure comprises a topplate configured to cover the coil assembly, the magnet assembly and thebearing assembly; and side supports secured to support the top plate.11. The sealed linear motor system of claim 9, further comprising atleast one encoder sensor coupled to the coil assembly, wherein the atleast one encoder sensor is configured to sense position and/or motioninformation of the magnet assembly.
 12. The sealed linear motor systemof claim 11, further comprising a magnetic encoder scale mounted to themagnet assembly and configured to produce an output corresponding to theposition and/or motion information.
 13. The sealed linear motor systemof claim 9, wherein each of the plate and the magnet housing comprisesstainless steel.
 14. A sealed linear motor system, comprising: a sealedcoil assembly having a plurality of coil windings and a first sealingmaterial to seal and to prevent moisture and/or chemical ingress intothe coil windings; a sealed magnet assembly disposed adjacent to thecoil assembly and comprising a plurality of magnets, a magnet housingdisposed to house, cover and seal the plurality of magnets within themagnet housing, a plate to cover the plurality of magnets, a sealingelement disposed between the plate and the magnet housing to seal themagnet assembly, and a groove formed to receive the sealing elementbetween the plate and the magnet housing; and at least one encodersensor sealed within the coil assembly and configured to sense positionand/or motion information of the magnet assembly.
 15. The sealed linearmotor system of claim 14, wherein the at least one encoder sensorcomprises a Hall-effect sensor and a magnetic encoder scale configuredto sense position and/or motion information of the magnet assembly. 16.The sealed linear motor system of claim 14, further comprising a motorstage structure coupled to the coil assembly or to the magnet assembly,and bearing assembly coupled to the motor stage structure to facilitatelinear motion of one of the magnet assembly or the coil assemblyrelative to the other.
 17. The sealed linear motor system of claim 14,wherein interior spaces of the coil assembly and the magnet assembly arefilled with a potting material.
 18. The sealed linear motor system ofclaim 14, further comprising: the first sealing material to seal thecoil windings to a base plate; and a second sealing material configuredto place and seal the plate and the magnet housing.
 19. The sealedlinear motor system of claim 18, wherein the first sealing materialcomprises a resin and the second sealing material comprises anelastomer.
 20. A sealed linear motor system, comprising: a sealed coilassembly having a plurality of coil windings and a sealing material toseal and to prevent moisture and/or chemical ingress into the coilwindings; a sealed magnet assembly disposed adjacent to the coilassembly and comprising a plurality of magnets, a magnet housingdisposed to house, cover and seal the plurality of magnets within themagnet housing, a plate to cover the plurality of magnets, a sealingelement disposed between the plate and the magnet housing to seal themagnet assembly, and a groove formed to receive the sealing elementbetween the plate and the magnet housing; and a sealed sensor assemblydisposed adjacent to the magnet assembly and having at least one encodersensor configured to sense position and/or motion information of themagnet assembly, wherein the sensor assembly comprises a stationaryenclosure comprising encoder sensor arrays and a movable enclosuredisposed about the stationary enclosure and comprising a magnet mountingbar.
 21. The sealed linear motor system of claim 20, wherein each of thestationary and movable enclosures comprises stainless steel.
 22. Thesealed linear motor system of claim 20, wherein interior spaces of thecoil assembly, the magnet assembly and the sensor assembly are filledwith a potting material.
 23. The sealed linear motor system of claim 20,further comprising a processing circuitry configured to process signalsfrom the sensor assembly to determine position information of the magnetassembly.
 24. A sealed linear motor system, comprising: a sealed coilassembly having a plurality of coil windings and a sealing material toseal and to prevent moisture and/or chemical ingress into the coilwindings; a sealed magnet assembly disposed adjacent to the coilassembly and comprising a plurality of magnets and a magnet housing tohouse, cover and seal the plurality of magnets within the magnethousing; a sealing element to seal the plurality of magnets in themagnet housing; and a groove formed in the magnet housing for sealingthe magnet housing with the sealing element.